Fix client crashing bug where loading the client with a small display area will cause the client to crash

Fix annoying Linux bug relating to painting events and peers

Fix settings saving bug where settings are saved to disk more often than they should

Fix RSInterface#isBeingDrawn bug affecting a limited amount of people

Drop Java 1.7 bytecode version for 1.8

Important: Since the downloadable RS client uses Java 7, it will no longer be compatible with Looking Glass. To make up for this, we will add support for using other clients such as RuneLite (at a later date).

This change was necessary to allow us to use Java 8 syntax. It also paves the way for Java 9/10/11 support.